pcistub_probe() is never called in atomic context.
This function is only set as ".probe" in struct pci_driver.
Despite never getting called from atomic context,
pcistub_probe() calls kmalloc() with GFP_ATOMIC,
which does not sleep for allocation.
GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL,
which can sleep and improve the possibility of sucessful allocation.
This is found by a static analysis tool named DCNS written by myself.
And I also manually check it.
Signed-off-by: Jia-Ju Bai <[email protected]>
---
drivers/xen/xen-pciback/pci_stub.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/xen/xen-pciback/pci_stub.c b/drivers/xen/xen-pciback/pci_stub.c
index 9e480fd..95e6ddd 100644
--- a/drivers/xen/xen-pciback/pci_stub.c
+++ b/drivers/xen/xen-pciback/pci_stub.c
@@ -577,7 +577,7 @@ static int pcistub_probe(struct pci_dev *dev, const struct pci_device_id *id)
}
if (!match) {
- pci_dev_id = kmalloc(sizeof(*pci_dev_id), GFP_ATOMIC);
+ pci_dev_id = kmalloc(sizeof(*pci_dev_id), GFP_KERNEL);
if (!pci_dev_id) {
err = -ENOMEM;
goto out;
--
1.9.1
On 04/09/2018 11:03 AM, Jia-Ju Bai wrote:
> pcistub_probe() is never called in atomic context.
> This function is only set as ".probe" in struct pci_driver.
>
> Despite never getting called from atomic context,
> pcistub_probe() calls kmalloc() with GFP_ATOMIC,
> which does not sleep for allocation.
> GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL,
> which can sleep and improve the possibility of sucessful allocation.
>
> This is found by a static analysis tool named DCNS written by myself.
> And I also manually check it.
>
> Signed-off-by: Jia-Ju Bai <[email protected]>
What about use of GFP_ATOMIC in pcistub_reg_add()?
-boris
> ---
> drivers/xen/xen-pciback/pci_stub.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/xen/xen-pciback/pci_stub.c b/drivers/xen/xen-pciback/pci_stub.c
> index 9e480fd..95e6ddd 100644
> --- a/drivers/xen/xen-pciback/pci_stub.c
> +++ b/drivers/xen/xen-pciback/pci_stub.c
> @@ -577,7 +577,7 @@ static int pcistub_probe(struct pci_dev *dev, const struct pci_device_id *id)
> }
>
> if (!match) {
> - pci_dev_id = kmalloc(sizeof(*pci_dev_id), GFP_ATOMIC);
> + pci_dev_id = kmalloc(sizeof(*pci_dev_id), GFP_KERNEL);
> if (!pci_dev_id) {
> err = -ENOMEM;
> goto out;
On 04/10/2018 10:31 AM, Jia-Ju Bai wrote:
>
>
>
> On 2018/4/10 22:27, Boris Ostrovsky wrote:
>> On 04/09/2018 11:03 AM, Jia-Ju Bai wrote:
>>> pcistub_probe() is never called in atomic context.
>>> This function is only set as ".probe" in struct pci_driver.
>>>
>>> Despite never getting called from atomic context,
>>> pcistub_probe() calls kmalloc() with GFP_ATOMIC,
>>> which does not sleep for allocation.
>>> GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL,
>>> which can sleep and improve the possibility of sucessful allocation.
>>>
>>> This is found by a static analysis tool named DCNS written by myself.
>>> And I also manually check it.
>>>
>>> Signed-off-by: Jia-Ju Bai <[email protected]>
>> What about use of GFP_ATOMIC in pcistub_reg_add()?
>
> Thanks for your reply :)
> I find pcistub_reg_add() is called by pcistub_quirk_add().
> And pcistub_quirk_add() is called in the macro DRIVER_ATTR().
> I am not sure whether DRIVER_ATTR() can make the function called in
> atomic context,
> so I do not analyze it in my tool.
I don't see why it needs to be ATOMIC, it's sysfs access. Can you send a
patch to fix it as well?
Thanks.
-boris
On 2018/4/10 23:01, Boris Ostrovsky wrote:
> On 04/10/2018 10:31 AM, Jia-Ju Bai wrote:
>>
>>
>> On 2018/4/10 22:27, Boris Ostrovsky wrote:
>>> On 04/09/2018 11:03 AM, Jia-Ju Bai wrote:
>>>> pcistub_probe() is never called in atomic context.
>>>> This function is only set as ".probe" in struct pci_driver.
>>>>
>>>> Despite never getting called from atomic context,
>>>> pcistub_probe() calls kmalloc() with GFP_ATOMIC,
>>>> which does not sleep for allocation.
>>>> GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL,
>>>> which can sleep and improve the possibility of sucessful allocation.
>>>>
>>>> This is found by a static analysis tool named DCNS written by myself.
>>>> And I also manually check it.
>>>>
>>>> Signed-off-by: Jia-Ju Bai <[email protected]>
>>> What about use of GFP_ATOMIC in pcistub_reg_add()?
>> Thanks for your reply :)
>> I find pcistub_reg_add() is called by pcistub_quirk_add().
>> And pcistub_quirk_add() is called in the macro DRIVER_ATTR().
>> I am not sure whether DRIVER_ATTR() can make the function called in
>> atomic context,
>> so I do not analyze it in my tool.
> I don't see why it needs to be ATOMIC, it's sysfs access. Can you send a
> patch to fix it as well?
Okay, I will send a patch for it soon.
You can have a look :)
Best wishes,
Jia-Ju Bai
On 04/09/2018 11:03 AM, Jia-Ju Bai wrote:
> pcistub_probe() is never called in atomic context.
> This function is only set as ".probe" in struct pci_driver.
>
> Despite never getting called from atomic context,
> pcistub_probe() calls kmalloc() with GFP_ATOMIC,
> which does not sleep for allocation.
> GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL,
> which can sleep and improve the possibility of sucessful allocation.
>
> This is found by a static analysis tool named DCNS written by myself.
> And I also manually check it.
>
> Signed-off-by: Jia-Ju Bai <[email protected]>
For all 5 patches:
Reviewed-by: Boris Ostrovsky <[email protected]>
On 04/09/2018 11:03 AM, Jia-Ju Bai wrote:
> pcistub_probe() is never called in atomic context.
> This function is only set as ".probe" in struct pci_driver.
>
> Despite never getting called from atomic context,
> pcistub_probe() calls kmalloc() with GFP_ATOMIC,
> which does not sleep for allocation.
> GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL,
> which can sleep and improve the possibility of sucessful allocation.
>
> This is found by a static analysis tool named DCNS written by myself.
> And I also manually check it.
>
> Signed-off-by: Jia-Ju Bai <[email protected]>
>
Applied the series and the extra patch to for-linus-4.17
-boris